#include "node.h"
#include "env.h"
#include "env-inl.h"
#include "util.h"
#include "util-inl.h"
#include "v8.h"

namespace node {

using v8::Array;
using v8::ArrayBuffer;
using v8::Context;
using v8::FunctionCallbackInfo;
using v8::HeapSpaceStatistics;
using v8::HeapStatistics;
using v8::Isolate;
using v8::Local;
using v8::NewStringType;
using v8::Object;
using v8::String;
using v8::Uint32;
using v8::V8;
using v8::Value;

#define HEAP_STATISTICS_PROPERTIES(V)                               \
    V(0, total_heap_size, kTotalHeapSizeIndex)                      \
    V(1, total_heap_size_executable, kTotalHeapSizeExecutableIndex) \
    V(2, total_physical_size, kTotalPhysicalSizeIndex)              \
    V(3, total_available_size, kTotalAvailableSize)                 \
    V(4, used_heap_size, kUsedHeapSizeIndex)                        \
    V(5, heap_size_limit, kHeapSizeLimitIndex)

#define V(a, b, c) +1
static const size_t kHeapStatisticsPropertiesCount = HEAP_STATISTICS_PROPERTIES(V);
#undef V

#define HEAP_SPACE_STATISTICS_PROPERTIES(V)              \
    V(0, space_size, kSpaceSizeIndex)                    \
    V(1, space_used_size, kSpaceUsedSizeIndex)           \
    V(2, space_available_size, kSpaceAvailableSizeIndex) \
    V(3, physical_space_size, kPhysicalSpaceSizeIndex)

#define V(a, b, c) +1
static const size_t kHeapSpaceStatisticsPropertiesCount = HEAP_SPACE_STATISTICS_PROPERTIES(V);
#undef V

// Will be populated in InitializeV8Bindings.
static size_t number_of_heap_spaces = 0;

void UpdateHeapStatisticsArrayBuffer(const FunctionCallbackInfo<Value>& args)
{
    Environment* env = Environment::GetCurrent(args);
    HeapStatistics s;
    env->isolate()->GetHeapStatistics(&s);
    uint32_t* const buffer = env->heap_statistics_buffer();
#define V(index, name, _) buffer[index] = static_cast<uint32_t>(s.name());
    HEAP_STATISTICS_PROPERTIES(V)
#undef V
}

void UpdateHeapSpaceStatisticsBuffer(const FunctionCallbackInfo<Value>& args)
{
    Environment* env = Environment::GetCurrent(args);
    HeapSpaceStatistics s;
    Isolate* const isolate = env->isolate();
    uint32_t* buffer = env->heap_space_statistics_buffer();

    for (size_t i = 0; i < number_of_heap_spaces; i++) {
        isolate->GetHeapSpaceStatistics(&s, i);
        size_t const property_offset = i * kHeapSpaceStatisticsPropertiesCount;
#define V(index, name, _) buffer[property_offset + index] = static_cast<uint32_t>(s.name());
        HEAP_SPACE_STATISTICS_PROPERTIES(V)
#undef V
    }
}

void SetFlagsFromString(const FunctionCallbackInfo<Value>& args)
{
    Environment* env = Environment::GetCurrent(args);

    if (args.Length() < 1)
        return env->ThrowTypeError("v8 flag is required");
    if (!args[0]->IsString())
        return env->ThrowTypeError("v8 flag must be a string");

    String::Utf8Value flags(args[0]);
    V8::SetFlagsFromString(*flags, flags.length());
}

void InitializeV8Bindings(Local<Object> target,
    Local<Value> unused,
    Local<Context> context)
{
    Environment* env = Environment::GetCurrent(context);

    env->SetMethod(target,
        "updateHeapStatisticsArrayBuffer",
        UpdateHeapStatisticsArrayBuffer);

    env->set_heap_statistics_buffer(new uint32_t[kHeapStatisticsPropertiesCount]);

    const size_t heap_statistics_buffer_byte_length = sizeof(*env->heap_statistics_buffer()) * kHeapStatisticsPropertiesCount;

    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(),
                    "heapStatisticsArrayBuffer"),
        ArrayBuffer::New(env->isolate(),
            env->heap_statistics_buffer(),
            heap_statistics_buffer_byte_length));

#define V(i, _, name)                                         \
    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(), #name), \
        Uint32::NewFromUnsigned(env->isolate(), i));

    HEAP_STATISTICS_PROPERTIES(V)
#undef V

    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(),
                    "kHeapSpaceStatisticsPropertiesCount"),
        Uint32::NewFromUnsigned(env->isolate(),
            kHeapSpaceStatisticsPropertiesCount));

    number_of_heap_spaces = env->isolate()->NumberOfHeapSpaces();

    // Heap space names are extracted once and exposed to JavaScript to
    // avoid excessive creation of heap space name Strings.
    HeapSpaceStatistics s;
    const Local<Array> heap_spaces = Array::New(env->isolate(),
        number_of_heap_spaces);
    for (size_t i = 0; i < number_of_heap_spaces; i++) {
        env->isolate()->GetHeapSpaceStatistics(&s, i);
        Local<String> heap_space_name = String::NewFromUtf8(env->isolate(),
            s.space_name(),
            NewStringType::kNormal)
                                            .ToLocalChecked();
        heap_spaces->Set(i, heap_space_name);
    }
    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(), "kHeapSpaces"),
        heap_spaces);

    env->SetMethod(target,
        "updateHeapSpaceStatisticsArrayBuffer",
        UpdateHeapSpaceStatisticsBuffer);

    env->set_heap_space_statistics_buffer(
        new uint32_t[kHeapSpaceStatisticsPropertiesCount * number_of_heap_spaces]);

    const size_t heap_space_statistics_buffer_byte_length = sizeof(*env->heap_space_statistics_buffer()) * kHeapSpaceStatisticsPropertiesCount * number_of_heap_spaces;

    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(),
                    "heapSpaceStatisticsArrayBuffer"),
        ArrayBuffer::New(env->isolate(),
            env->heap_space_statistics_buffer(),
            heap_space_statistics_buffer_byte_length));

#define V(i, _, name)                                         \
    target->Set(FIXED_ONE_BYTE_STRING(env->isolate(), #name), \
        Uint32::NewFromUnsigned(env->isolate(), i));

    HEAP_SPACE_STATISTICS_PROPERTIES(V)
#undef V

    env->SetMethod(target, "setFlagsFromString", SetFlagsFromString);
}

} // namespace node

NODE_MODULE_CONTEXT_AWARE_BUILTIN(v8, node::InitializeV8Bindings)
